The present invention relates to the gas switching valves or servovalves operated by fluid pressure by way of a diaphragm and which act under the control of an auxiliary valve, and to the arrangement and assembly of combustion control devices in a gas heating appliance.
Valves arrangements are known for the automatic control of the gas flow in an artificial gas fireplace, as described in U.S. Pat. No. 5,674,065, wherein an electromagnetic switching valve is supplied by the voltage self-generated by a thermopile heated by a pilot flame, the valve being switched by a bimetal thermostat located away from the burner, in response to the variations in temperature of the heated area. At the gas supply intake this known flow control device has an electromagnetic safety valve energized by a flame thermocouple.
Valves with a manual gas flow regulating control are used for the burners of portable stoves and gas cookers, such as the type described in U.S. Pat. No. 5,375,585 with a rotary taper valve member, and which has a built-in electric switch operated by pressing the stem manually and an electromagnetic safety valve energized with a flame thermocouple, for ignition purposes.
EP-319257-A shows a valve arrangement for a gas heating appliance, comprising a first manual valve with various positions activating a pilot flame igniter and permitting the passage of the gas flow to the block of series valves, activated by remote control to supply a burner.
U.S. Pat. No. 4,073,611 discloses a valve arrangement for gas control in a burner appliance, comprising a first electromagnetic safety valve controlling a pilot flame, and a second main valve for controlling the burner supply, the flow of gas being received from the first valve, means for igniting the pilot flame and for flame detection, and an electrical circuit for energizing the igniter and the second valve.
Gas flow switching servovalves are also known, such as the one described in U.S. Pat. No. 3,880,186, which is operated by way of a diaphragm by the difference in pressure in the chambers on both sides, controlled by an auxiliary electromagnetic bleed valve.
The object of the present invention is a gas valve arrangement for controlling the gas flow in a gas heating appliance for an area, which works automatically, governed by an electronic circuit and supplied by a low voltage battery.
Due to the lower power consumption required for controlling the gas valve arrangement, a first regulating valve or tap is operated by hand by means of a rotary control and a second switching valve or servovalve fitted in series with the first one is operated by gas pressure by means of a diaphragm, with the assistance of an auxiliary low-power electromagnetic valve, and in response to a room temperature thermostat, which does not consume electric power either. The manual valve has a rotary control, while the valve stem in turn is axially sliding and pushes an electromagnetic safety valve for its initial opening which is built into the gas supply inlet to the manual tap.
The operation of the valve arrangement is automatic, since the initial actuation of the stem of the first valve, besides allowing gas to flow to the pilot flame, provides the igniter supply and energizes the safety valve by way of the control circuit. The electronic control circuit may also be activated from a remote control, acting on the ignition and safety valve energizing. The switching servovalve has to be operated with very little electric power.